1. Field of the Invention
The present invention relates to measurement and logging of salinity of fluids in well bores.
2. Description of the Related Art
Salinity measurement of fluid in a well borehole is important to evaluate the formation fluid. Salinity measurement can help in delineating oil and water and to estimate the moveable oil in a reservoir. Measurement of salinity as a function of well depth helps in differentiating between fresh and saline water and can help in identifying invasion of salt water into a producing borehole.
The downhole fluid environment is complex with presence of multiple non-homogenous phases with variable velocities. Measurement of a particular fluid characteristic performed at a single point in the wellbore might not represent an accurate representation of actual borehole fluid salinity.
So far as is known, downhole salinity measurement methods have in the past primarily been based on acoustic wave propagation through the formation fluid. Examples are U.S. Pat. No. 4,754,839 and U.S. Published Patent Application No. 2011/0114385.
U.S. Pat. No. 7,129,704 related to electromagnetic detection of progression of salt water fronts headed through formations to a water well. The increase of salt water in the formation before intrusion into the well water was measured with widely spaced electrodes since a significant portion of the induced electromagnetic field was required to pass through formation water outside the well bore.